<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表格</title>
    <style>
        table{
            width: 300px;
            height: 300px;
            margin: auto;
            border: 1px solid black;
        }
        table tr{
            border: 1px solid red;
        }
        table tr td{
            border: 1px solid red;
            text-align: center;
        }
        /* colspan  lowspan  来进行单元格合并 */
    </style>
</head>
<body>
    <table>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
        </tr>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
        </tr>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
        </tr>
    </table>
</body>
</html>